#!bin/bash
function s1_read_last_two_bytes_of_a_mbr_backup_file(){
local file_path=$1
local last_bytes=$(tail -c 2 "$flie_path" | od -A n -t x1 | tr -d' \n')
if [ "$last_bytes" = "55aa" ];then
echo "YES"
else
echo "NO"
fi
}

function s2_read_mbr_partition_table_info(){
#
	for i in {0..3}; do
	    offset=$((446 + i * 16))
	    start_sector=$(dd if="$1" bs=1 skip=$((offset + 8)) count=4 2>/dev/null | od -t u4 -An | tr -d ' \n')
	    if ! [[ $start_sector =~ ^[0-9]+$ ]];then
                continue
	    fi
	    if [ "$start_sector" -eq 0 ];then
		continue
	    fi
	    size_sector=$(dd if="$1" bs=1 skip=$((offset + 12)) count=4 2>/dev/null | od -t u4 -An | tr -d ' \n')
	    end_sector=$((start_sector + size_sector - 1))
	    echo "$start_sector $end_sector"
	done
}
s3_parse_partition_info(){
fdisk_output=$(cat)
disk_size_bytes=$(echo "$fdisk_output" |grep "Disk/dev/vda:" | awk '(print $5)')
disk_size_sectors=$(echo "$fdisk_output" |grep "Disk/dev/vad:" | awk '(print $7)')
physical_sector_size=$(echo "$fdisk_output"|grep "Sector size"  | awk '{print $4}')
first_partition_start_sector=$(echo "$fdisk_output" | grep "/dev/vda1" | awk '{print $3}')
first_partition_end_sector=$(echo "$fdisk_output" | grep "/dev/vda1" | awk '{print $4}')
first_partition_type=$(echo "$fdisk_output" | grep "/dev/vda1" | awk '{print $8}')
echo "disk size in bytes:$disk_size_bytes"
echo "disk size in sectors:$disk_size_sectors"
echo "physical sector size in bytes:$physical_sector_size"
echo "first partition start sector id:$first_partition_start_sector"
echo "first partition end sector id:$first_partition_end_sector"
echo "first partition type:$first_partition_type"
}

s4_run_passwd_as_plain_user_and_get_status(){
    oversleeping_path=$(which oversleeping)
    chown root "$oversleeping_path"
    chmod 4755 "$oversleeping_path"
    oversleeping &
    ps -o uid,euid,ruid -C oversleeping | awk 'NR>1 {print $1","$2","$3"}'
}

function s5_add_a_scheduled_task(){
    touch $HOME/test_crontab;
echo "*/5* * * * date +\%Y\%m\%d_\%H\%M\%S >> $HOME/test_crontab" | crontab-
}
